<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    <style>
        .dd{
            width: 200px;
            height: 200px;
            background: red;
        }
    </style>
</head>
<body>
    <div id="app">
        <button @click="fn">toggle</button>
        <div class="dd" v-show="bol"></div>
    </div>
    <script>
      new Vue({
            el:"#app",
            data:{
                bol:false,
            },
             methods: {
                fn() {
                    this.bol = !this.bol;
                }
            }
        })

    </script>
    
</body>
</html>